A vehicular lamp has been known which includes a light guide that is disposed to extend in a left-and-right direction and a front-and-rear direction (Japanese Patent Laid-Open Publication No. 2011-216279). In such a light guide, a plurality of steps are formed on the rear side surface of the light guide along the extension direction of the light guide. Hence, light traveling through the light guide is reflected by the plurality of steps, and the reflected light is emitted toward the front side of the vehicular lamp through a front cover. By providing the steps on the rear side surface of the light guide, the entire light guide may be made to uniformly glow.